Hi, I’m using windows 10 with audacity 2.1.2 (obtained with .exe installer).
I have been editing some audiobooks with audacity to merge several tracks so each chapter is only one track. When I export my new mixed track to .wav or .mp3 and then reload it into audacity, the waveform amplitude has increased considerably (which is not due to scaling) and there is voice distortion in the playback. What can I do to prevent this happening or to fix it? It might be something simple but it’s been a while since I’ve used audacity.
Mixing (such as mixing a music background track with voice) is done by summation and the amplitude will increase. Equalization or other effects can also increase the level.
Audacity itself won’t clip (distort) so if you don’t have the playback volume at maximum you may not hear any distortion until you export.
If you are not mixing, normalize (with the Normalize or Amplify effect) before exporting. If you are mixing, you can export to floating-point WAV (which is not limited to 0dB). Then re-import, normalize, and export to your desired final format.
Note that MP3 is lossy compression. The wave shapes change and some peaks get higher and others lower. It’s not unusual for the highest peaks to go up by 1dB when you compress to MP3, so some people like to normalize to -1dB or so before exporting to MP3.
Hi, no, it doesn’t happen with just a pure import then export. My workflow is: import multiple tracks - time shift tracks end-to-end - mix and render to new track (ctlr+shift+m) - export new track to 16-bit wav with new metadata. When I re-import, the waveform amplitude has increased. In the original tracks, it never goes beyond +/- 1.0, and rarely goes beyond +/-0.7. I’ve taken a screenshot for comparison. The original is the top track, the reimported wav is the bottom track.
I know I’m techinically mixing, but as none of the original tracks overlap, I don’t think the amplitude should be increased, right? I have tried normalizing before exporting, but it does not solve the issue. Any thoughts?
The track Gain control (http://manual.audacityteam.org/man/audio_tracks.html#gain) will affect the amplitude of the exported file (but does not change the appearance of the waveform until the track is mixed down / rendered / exported). If the track Gain control is higher than zero, the exported waveform will have greater amplitude than the track.